Method and apparatus for updating announcement group information

BACKGROUND OF THE INVENTION

The present invention relates generally to wide area communications systems. More particularly, the present invention relates to a method and apparatus for updating announcement group information within a wide area dispatch system.

In normal processing of a wide area trunked system, communication unit or radio (hereinafter referred to as a “subscriber unit”) receives the announcement group ID of its affiliated talkgroup upon performing talkgroup affiliation. However, if the talkgroup to announcement group database in a zone controller is not available for use, the announcement group information cannot be delivered to the subscriber unit. For example, the talkgroup to announcement group database is not available when the database has not been configured by the zone manager. When the database has not been configured, it is not possible for the database to provide information about the announcement group. As a result, when the subscriber unit affiliates to a talkgroup and the talkgroup does not have a preconfigured announcement group, the zone controller will respond to the subscriber unit with an unknown announcement group signal (for example, Null group ID=0). Alternatively, when a site cannot communicate with the zone controller, i.e., it is in site trunking, the zone controller cannot deliver information about the announcement group to the site. A subscriber unit, therefore, may receive an unknown announcement group signal. Both of these situations are problematic because the subscriber unit may not be able to participate in calls for the announcement group that it was intended to receive.

When the zone controller database is configured or the site recovers from site trunking, current systems do not notify the subscriber unit of the updated information about the announcement group. The subscriber unit, therefore, will not be aware of the updated announcement group and will not receive calls it was intended to receive. As a result, there is a need for a method and an apparatus that detects when a subscriber unit is operating with an unknown announcement group signal and in response thereto sends a signal updating the announcement group to the subscriber unit.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating a wide area dispatch system and the relationship of a zone manager, zone controller, and a plurality of communication sites;

FIG. 2 is a diagram illustrating the relationship between announcement groups, talk groups and subscriber units;

FIG. 3 is a flow diagram illustrating the operation of one embodiment of the present invention;

FIG. 4 is a flow diagram illustrating the operation of another embodiment of the present invention; and

FIG. 5 is a flow diagram illustrating the operation of a further embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an improved method and apparatus for updating a subscriber unit with announcement group information. In processing a wide area communications system a subscriber unit will not receive announcement group identification or information when the announcement group database is not available, e.g., when the database has not been configured by the zone manager or the site is in site trunking and cannot communicate with the zone controller.

The present invention is directed to a method and apparatus of updating subscriber units that previously received an unknown or out of date, i.e., pre-updated, announcement group identification. The method of the present invention includes an embodiment where a subscriber unit requests affiliation with a talk group. A pre-updated announcement group identification is issued in response to the request for affiliation. Information that identifies which subscriber unit received the pre-updated announcement group signal is stored. An updated announcement signal is subsequently sent to the subscriber unit. In a first embodiment, the zone controller includes a database that determines which subscriber units have received a pre-updated announcement group identification. The zone controller requests affiliation from these subscriber units and provides an updated group announcement identification. In a second embodiment, a site includes a database that stores information that identifies which subscriber units have received a pre-updated announcement group identification. The site forwards the information that identifies the subscriber units to the zone controller. The zone controller then requests affiliation from the subscriber units and forwards an updated group announcement identification.

This invention solves the problem of having subscriber units operating within a system with a pre-updated announcement group identification. The goal of this invention is to determine which subscriber units have received a pre-updated announcement group identification and update these individuals with the correct, predefined announcement group identification.

The present invention, together with attendant objectives and advantages, will be best understood with reference to the detailed description below, read in conjunction with the accompanying drawings.

Referring to FIG. 1, a wide area dispatch system <b>100</b> modeled on systems such as Motorola's SmartZone® and OmniLink® systems is illustrated. Generally, these systems include a central controlling element which communicates with a multitude of communication sites. With particular reference to FIG. 1, the system <b>100</b> includes a zone manager <b>110</b>, a zone controller <b>114</b>, and a plurality of sites <b>116</b>. The zone manager <b>110</b> is responsible for configuring system parameters such as physical device configuration parameters. The zone controller <b>114</b> performs call control and mobility management for subscriber units. The zone controller <b>114</b> is coupled to the sites <b>116</b> via communication trunks <b>118</b>. The zone controller <b>114</b> is connected to the zone manager via the communication trunk <b>120</b>. The sites <b>116</b> provide the over-the-air signaling and are the interface point with the subscriber units. The sites <b>116</b> include a plurality of communication resources or channels <b>122</b> (generally frequencies in an FDMA, CDMA, or TDMA system) for over-the-air-communication with subscriber units.

With reference to FIG. 2, the relationship of an announcement group <b>200</b>, talkgroups <b>202</b><i>a</i>-<b>202</b><i>c </i>and the subscriber units <b>210</b><i>a</i>-<b>210</b><i>i </i>are illustrated. Talkgroups <b>202</b><i>a</i>-<b>202</b><i>c </i>are groupings of subscriber units <b>210</b>, or individuals, that wish to intercommunicate. The zone manager <b>110</b> is responsible for configuring system parameters such as talkgroup <b>202</b> attributes such as priority levels and security capabilities. A subscriber unit <b>210</b> is considered a member of the talkgroup <b>202</b> when it affiliates to a particular talkgroup <b>202</b>. Talkgroups <b>202</b> are grouped together in a predefined structure known as a fleet. It is possible to communicate to all subscriber units <b>210</b> in a talkgroup <b>202</b> in a common fleet. In order to communicate with the fleet members, a call is placed on a predefined talkgroup <b>202</b><i>a</i>-<b>202</b><i>c </i>assigned to the fleet or, in other words, a fleetwide talkgroup. This fleetwide talkgroup is referred to as an announcement group <b>200</b>.

The subscriber units <b>210</b><i>a</i>-<b>210</b><i>i </i>are individual units (e.g. radios) for users that transmit and receive information such as voice and data. Subscriber units <b>210</b><i>a</i>-<b>210</b><i>i </i>register at sites <b>116</b> for communication via a site <b>116</b>. The subscriber units <b>210</b> are capable of (1) making individual calls on the system <b>100</b> from one subscriber unit <b>210</b> to another subscriber unit <b>210</b>; (2) talkgroup calls, which are broadcast to all subscriber units <b>210</b> affiliated with a particular talkgroup <b>202</b>; (3) announcement group calls, which are broadcast to all subscriber units <b>210</b> affiliated with an announcement group <b>200</b>; or (4) telephone interconnect calls, which require a zone controller <b>114</b> to interconnect calls with the public switched telephone network (PSTN) through an interface (not shown).

As an exemplary grouping, in FIG. 2, subscriber units <b>210</b><i>a</i>-<b>210</b><i>c </i>are shown affiliated with a first talkgroup <b>202</b><i>a</i>. Subscriber units <b>210</b><i>d</i>-<b>210</b><i>f </i>are shown affiliated with a second talkgroup <b>202</b><i>b</i>. Subscriber units <b>210</b><i>g</i>-<b>210</b><i>i </i>are shown affiliated with a third talkgroup <b>202</b><i>c</i>. The first talkgroup <b>202</b><i>a</i>, the second talkgroup <b>202</b><i>b</i>, and the third talkgroup <b>202</b><i>c </i>are associated with the announcement group <b>200</b>.

When a site <b>116</b> is communicating with the zone controller <b>114</b> it is considered to be in wide area trunking since it has the ability to be linked to other sites <b>116</b>. If a site <b>116</b> cannot communicate with the zone controller <b>114</b> for any reason, the site <b>116</b> will enter a state known as site trunking. When in site trunking, all subscriber units <b>210</b> at a site <b>116</b> can communicate only with other subscriber units <b>210</b> active at that particular site <b>116</b>.

Referring again to FIG. 1, the zone controller <b>114</b> has a database that contains the relationship between announcement group <b>200</b> and the talkgroups <b>202</b>. When a subscriber unit <b>210</b> affiliates to a particular talkgroup <b>202</b>, it signals its individual ID and the affiliated talkgroup <b>202</b>. Upon receiving this affiliation request, the zone controller <b>114</b> will examine its database to determine the announcement group <b>200</b> associated with the affiliated talkgroup <b>202</b> and respond to the affiliation request with an acknowledgement that includes the talkgroup's assigned announcement group <b>200</b>. The subscriber unit <b>210</b> will then use this announcement group <b>200</b> to receive fleetwide calls.

FIG. 3 is a flow diagram illustrating one of the embodiments of the present invention. At block <b>301</b>, a subscriber unit <b>210</b> requests affiliation to a talkgroup <b>202</b>. At block <b>303</b>, the state of the site <b>116</b> is determined. If the site <b>116</b> is in site trunking, the site <b>116</b> will issue an affiliation response with the unknown announcement group as shown at block <b>305</b>. The site <b>116</b> will then, at block <b>309</b>, store in a database the subscriber unit ID as a unit that has received an unknown announcement group signal. If, at block <b>303</b>, the site <b>116</b> is in wide trunking, the site <b>116</b> forwards the affiliation request to the zone controller <b>114</b>. At block <b>307</b>, the zone controller <b>114</b> searches its database for the proper announcement group <b>200</b>. If, at block <b>311</b>, the zone controller <b>114</b> cannot find the preconfigured announcement group <b>200</b> for this talkgroup <b>202</b>, the zone controller <b>114</b> will then issue an affiliation response with that announcement group as indicated at block <b>313</b>. If, at block <b>311</b>, the zone controller <b>114</b> can find the preconfigured announcement group <b>200</b> for the talkgroup <b>202</b>, the zone controller <b>114</b> will issue an affiliation response with the unknown announcement group signal as indicated at block <b>315</b>.

FIG. 4 shows how the zone controller <b>114</b> could update the subscriber units <b>210</b> which are operating with pre-updated announcement group information as a result of the talkgroup to announcement group database not being configured. Alternately, the zone manager <b>110</b> may modify or update an already valid and configured announcement group to another valid announcement group. At block <b>401</b>, the zone controller <b>114</b> receives the announcement group <b>200</b> from the zone manager <b>210</b>. The zone controller <b>114</b> will now know the correct updated announcement group <b>200</b> for talkgroups <b>202</b>. At block <b>403</b>, the zone controller <b>114</b> will determine which subscriber units <b>210</b> are affiliated to talkgroups <b>202</b> that did not previously receive an updated announcement group <b>200</b>. At block <b>405</b>, the zone controller <b>114</b> will issue a request for affiliation message to each of these subscriber units <b>210</b>. Upon receiving the request for affiliation message, a subscriber unit <b>210</b> will send in an affiliation request. If the subscriber unit <b>210</b> does not respond (block <b>406</b>), multiple requests will be made, at block <b>408</b>, until the subscriber unit <b>210</b> responds. The zone controller <b>114</b> then receives the affiliation request from a subscriber unit <b>210</b> and, at block <b>407</b>, sends a response back to the subscriber unit <b>210</b> with the correct announcement group information <b>200</b>.

FIG. 5 shows how the zone controller <b>114</b> could update the subscriber units because of a site trunking state. In this case, a site <b>116</b>, while in the site trunking state, could store in a database the ID's of the subscriber units <b>210</b> that received the unknown announcement group (FIG. 3 block <b>309</b>). In a preferred embodiment, when the site <b>116</b> recovers from site trunking, the site <b>116</b> could upload information to the zone controller <b>114</b>. This upload information would consist of an ID of each subscriber unit <b>210</b> at the site <b>116</b> and a list of those subscriber unit IDs <b>210</b> that have received an unknown announcement group. Once the zone controller <b>114</b> receives the upload information from a site <b>116</b>, the zone controller <b>114</b> could notify those subscriber units <b>210</b> with the unknown announcement group to affiliate again so that the announcement group ID could be corrected. With reference to FIG. 5, at block <b>501</b>, a site <b>116</b> transitions from site trunking to wide trunking. The site <b>116</b> can now communicate with the zone controller <b>114</b> and can start to send site <b>116</b> upload information. At block <b>503</b>, the site <b>116</b> sends upload information to the zone controller <b>114</b> including the ID information of the subscriber units <b>210</b> that received the unknown announcement group. Once the zone controller <b>114</b> receives this subscriber unit ID information (block <b>505</b>), the zone controller <b>114</b> can then issue each of these subscriber units a request for affiliation (block <b>507</b>). When a subscriber unit <b>210</b> receives the request for affiliation, the subscriber unit <b>210</b> will send in an affiliation request. At block <b>509</b>, the zone controller <b>114</b> receives the affiliation request from the subscriber unit <b>210</b> and sends a response back with the correct announcement group <b>200</b>.

In another embodiment directed to a situation of site trunking, in block <b>505</b>, when the zone controller <b>114</b> receives the upload information from a site <b>116</b>, the zone controller <b>114</b> could send a request for affiliation, at block <b>507</b>, to every individual at the site <b>116</b> rather than just the individuals that receive the unknown announcement group signal. In this case, the site <b>116</b> would not need to keep track of the subscriber units <b>210</b> that were issued the unknown announcement group signal. In another embodiment, in blocks <b>507</b> and <b>509</b>, the zone controller <b>114</b> could send an affiliation response with the predefined announcement group <b>200</b> to one or more subscriber units <b>210</b> without first requesting the subscriber units <b>210</b> to affiliate.

The present invention includes advantages not found in previous communications systems such as helping a subscriber unit <b>210</b> to avoid missing calls it was intended to receive. For example, the present invention provides for subscriber units <b>210</b> with the unknown announcement group to be quickly updated with the correct announcement group <b>200</b> in a timely manner without relying on the subscriber unit <b>210</b> to take an action (such as changing talkgroups <b>202</b> or sites <b>116</b>). Also, the subscriber unit <b>210</b> does not have to be preprogrammed with an announcement group <b>200</b>, allowing the flexibility of changing the announcement group <b>200</b> without reprogramming the subscriber unit <b>210</b>. In addition, the present invention does not require a talkgroup to announcement group database at each site <b>116</b> thereby reducing the complexity of the system by keeping a distributed database up to date.

While particular embodiments of the present invention have been shown and described, modifications may be made. For example, method steps may be rearranged, substituted and deleted as appropriate. Further, structural elements may be rearranged and substitutions may be made while still providing the required function. It is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention.